Conversion of hydrocarbon oils



Oct. 5, 1943. DU Bols l-:AsTMAN ET AL 2,330,816

CONVERSION OF HYDROCARBON OILS Filed Deo. sul, 1940 condensate is in a reaction zone.

Patented Oct. 5, 1943 COVERSION OF HYDROCARBON OILS du Bois llastmanl and Joseph Mason Barron Port Arthur, Tex., assignors, by mesne assignments, to The Texas Company, l

New York, 4 l i N. Y.a corporation of Delaware Application December 31, 1940,

'e claims. `(c1. "19e-49) This. invention relates to a combination thermal cracking and coking and catalytic cracking process for the production of a maximum yield of high antiknock gasoline or motor fuel.

.The invention contemplates `a methodr of processing in a unitary operation relatively light charging stocks adapted for catalytic cracking and heavier charging stocks adapted for thermal cracking. In accordance with kthe invention a stock suitable for catalytic cracking such as gas oil is lsubjected to catalytic cracking `while the lheavier stock such as topped orreduced crude petroleum is introduced into a fractionating zone in which vapors from the thermal cracking and coking operations are substituents of the heavy jected to fractionation and wherein a resultant mixture ofunvaporized charging stock and re# flux condensate is separated iromuncondensed vapors. The latter vapors are ther fractionation-to `separate adesired gasoline or naphtha distillate Yfrom, reiiux condensate which is cycled to a heating zone' in which the heated to a crackingtemperature. The products from the' catalytic cracking operation and the mixture of unvaporized charging stock and reflux condensate fromthe fractionating zone are combinedwith the heated products from the heating Zone for thermal cracking i'I'he cracked products are separated into vapors, and residue and the residue is passed to a coking zone wherein conversion to `a coke residueoccurs. YIn accordance with the invention a portion of the vapors sufficient to effect coking is included with the residue which is passed to the cokng zone. `By including such portion of vapors with the resisubjected to furv Y mixed with products serial No. 372,453

from a recycling heating or cracking coil. The heavy fraction is advantageously charged to the dephlegmator receiving vapors from the `thermal cracking operation andthe resultant mixture of reflux condensate and .unvaporized confraction is brought into contact with the `heated products from` a recyclingthermal cracking zoneand the mixture subjected to cracking in a reaction Zone.` lighter fraction from the crude 4fractionation is directed to alcatalytic cracking zone and products from the catalyticrcracking zone are adfrom the thermal recycling heating or crackingzone andV with the mixture of heavy reflux condensate and unvaporized constituents of the heavyifraction from the crude. The commingled constituents areV subjected to o cracking andthe crackedl products separated due it is possible to effect autogencus coking of the vapors fromthe cracking operation.

The invention'contemplates a process wherein` charging stock suchas crude `petroleum is fractionated to form a heavy fraction adapted for thermal cracking and a lighter fraction" adapted for catalytic cracking. {The heavy fraction is.V

thermal cracking op' subjected to cracking in a eration by being combined with the hot products I cracked productsk may into vapors and. residue,v the presdue converted to coke, the evolved vapors from both the cracking and coking operations dephlegmated with the heavy fraction from the crude and the vapors furtherV fractionated to form aclean re-` cycle stock for passage to the thermal heating coil. t

The thermal recracking of the catalytically cracked products conditions such products or renders them suitable for further.` catalytic cracking and in accordancefwith the invention the products resulting Yfrom the thermal cracking, including the recracking of the catalytically cracked products, are; fractionated to separate out heavy constituents adapted for being combinedwith the products from the recycling condensate heating coil and lighter or intermediate constituents adapted for recycling to Ythe heating or crackingV coil and adapted also for cracking in the catalytic cracking zone.

In 'a modification of the invention products from" the catalytic cracking operation are delivered to the fractionating zone of the thermal cracking operation so that the catalytically be fractionated together `with the thermally cracked products and heavier constituents ofthe catalytic cracking passed to the `thermal cracking zone while the gasoline ormotor fuel constituents are collected together Withthe thermally cracked gasoline or `motor fuel constituents.

For the purpose of more fully disclosing the invention reference is 4now had to the accompanying drawing which is a ilow diagram indicating an apparatus adapted for the practice ofthe invention. r. 1 l`Referring to the drawing the charging stock The through a heating coil line i6 and directed suitable for catalytic cracking.`

aluminaory silica. or

such as crude source by a Dump petroleum is drawn from a suitable Il] which directs the charge il which is suitably heated by heat exchange with hot cracked products of the system or otherwise to raise the oil to a desired distilling temperature; The heated v.oil is `discharged into a towenl?. for separation into vapors and residue and fractionation of the vapors. A condensate fraction suitable for catalytic crac-king is collected on a tray i3 and lighter vapors pass overhead toa condenser coil"- M, light distillate such as naphtha or gasoline' being collected in a receiving drum l5. Y Y

Condensate from tray l3`is drawn througha I8 to a heating coil adapted for heating the oil to a passes from the heating coil to 2| containing a bed of catalytic material.'

The catalyst consists advantageously of a synthetic silica-alumina typeof catalyst.- Various Y acid-'treated and metal-substituted'claysv such a's and acid-treated. and #metalor articial Zeolites, suchas the Super-Filtrols substituted natural the' artificial zeolite known as Doucil may be includes-a heating coil ft2.y mountedrin a-:suitable lfurnace 23,` a. reactionand separating chamber l'ailtwa cokingdrum 25,- ia'f primary fractionating t'ow'erw 251 and a secondaryfractionating tower 27. Residue` from the crudenstripping tower. I2` is drawn by pump' 28and directed througha line 29 to the fractionating tower 26 wherein .the vapors.' are .dephlegmated with the crude residuum and a' resultant .mixture of v heavy.reux ccindensate.v and' unvaporiz'ed residue is collected This'mixture is withdrawn by-a pumpf 3| and transfer line 33e`xte`n'ding from the heating coil 22ltc "the reaction. chamber 2li, so thatthemixture voltreiiux condensate and unvaporized crude residuum is combinedzfwith the hot products from the? heating vcoil 22 for cracking .in the .reaction chamber 24. Separation of vapors: from res`idue takes place in the reaction chamber andresidue is withdrawn throughsa'line' 34 having a pressure reducing Valve 35 and extendingY to, the coking drum 25. Separated vapors pass from the reli i -action chamber through a'va'p'or line 3B having. a

pressure reducing valve 3l!` and extending: to the tower 25, the Vapor line preferablyenteringthe tower above theltrapout tray 323. yVaporsfirom the-.coking drum 25 pass through. Yline 3.8:to1a

- lower Vsection39 of the tower 'beneaththe tray Sin which section the l-vapors: from the'. coking operation are subjected to:a primary condensation or dephlegmation to formia heavy.Y tarry distillate .whichrmay bewithdr Wn through a line 40.; Aportion of the reflux 4condensate from tower .27. mayv loe'v cooled and-1 reluXedin the dephlegmatori)` and: aI portionv ofthe tarryfgdisr tillate withdrawn through line 40,may begcycled hackV to the; chamber .Sil-fte. provide 'liquid ,flow

passed throughl a'linex32; to a i ucts from thecoil 22- as well by a pump l'l through' aline:n 'l

I disposed in afurnace 20.-

temperature The heated oil.r a catalyst case` ytherein to prevent deposition of coke. The 'uns condensed vapors pass from tower 2G through a Ypassed through; a' line 6 to the transfer line 33 to be commingled therein with the heated prode as with the mixture When passing the products from the catalytic cracking operation to the reaction chamber 24 cient to insure the delivery 'of reactionl chamber. lmaintain lpressures the'products to the It is generally desirable to approximating 260 lbs. or

- even higher in the thermal reactionchamber 24 land consequently the pressure inthecatalyst case should be somewhaty higher,y for example, 210 lbs;

'Ina such operatic-n it is sometimes desirabley to carry on cracking in the heating'coil 22: at. a pressure somewhat Vhigherthan is maintainedfin the'reaction` chamber 2A and, for tliislqpurpose` a pressure reducing valve lidmay beinse'rted in the transfer line 33. Thus, fcrexaxnple, the heating coil outlet may be heldat a pressure of 40G-lbs. andthe pressure dropped to about 200 lbs. in the reaction chamber 2S while a pressure of v 205-21011@ is maintainedfinthe catalyst easel 2|.

; accommodate thegfcataly-tic:

thermal cracking operation. back to the catalytic cracking-zone. For this purpose.linerllL/naybe' equipped with a branchiline-GB extending 'tera through theV heating gcoil; l9fwherein-it is; heated sufficiently to .maintain crackingv temperatures' of the orderof B50.D 1'..1050, Flx'and preferably.` temperatures ofabout-.91.0 liter-1000?` E-fintthe' catalyst case. When using*thecatalystsdisclosed herein relatively :lowj superatmospheric; pressures under 100 lbs.` and even; proximately' atmospheric;

. but when directing the catalytically crackedprodiucts tothel reaction .chamber vZkllit is necessary-3130 sidual products of,

.reflux condensate drawn from the suretolthatemployed inthe thermal reaction chamber where"pressures upwards of 200 lbs. are generally desirable,although pressures approximately as 'low asvlOO lbs. may at times be employed. The reflux condensate `cycled from the tower 21 to theheatingicoil 22 is subjected to temperatures ofV the order of `950" F. to `1050ol FL under superatmospheric pressures such as 400- 800 lbs. The topped or reduced crude from the crude stripping tower is directed tothe fractionator 26 and the resultant mixture of refluxcondensate and "crude residuurn ata temperature of the order of 750 F..to about'800F. is withdrawn from'the tray-30 and combined with the heated products from coil 22 and with the products from the catalytic cracking chamber 2| for reactionin the thermalreaction'chamber'Zll 4wherein the are dephlegm'ated in' chamber 39 to form a heavy tarry condensate [which constitutes a distillate fuel oil product.`V If` desired this `product maybe flash distilledto'produce a final fuel oil product of desired gravity or flash test. The'pressure in the fra'ctionator 2c will normally approximate the i pressure in the coking drum 25.

I The operation in which the products from the catalytic 'cracking case ,2I are directed topline 4T to the fractionatcr 26`has a particular advantage in that it facilitates the maintenance of relatively low 'pressures in the catalyst case which low pressures,` as has been stated, are quite satisfactory. In' this operation the residual products of the catalytic cracking together with the rethe topped ror reduced crude charging stockwhich collect on the tray 30 are combinedwith'the heated'vcycle condensate for cracking in the reaction chamber 24, while lighter constituents of the catalytic cracking are distilled over into the tower 21.

In some cases, particularly when the crude residual stock charged to the tower 26 contains relatively large proportions of gas oil constituents, it is advantageous to pass a portion of the tower 21 to the catalytic cracking zone.

The heavy, tarry condensate withdrawn from separator 39 through line 40 makes an excellent fuel oil but in case such a product is not desired, the tarry condensate may be directed to the reaction ohamber 24, or preferably to the coking drum 25.

While we have described a particular embodiment of our invention for purposes of illustration, it should be understood that various modifications and adaptations thereof which will be obvious to one skilled in the art, may be made within the spirit of the invention as set forth in the appended claims.

We claim:

1. In the conversion of hydrocarbon oils the process that comprises distilling crude petroleum to separate a residue from a lighter fraction, subjecting said lighter fraction tov catalytic cracking, introducing said residue intoA a fractionating zone whereiny fractionation takes place to separate a resultant mixture fof unvaporized residue and heavy` reflux condensate from uncondensed vapors, subjecting the unoondensed vapors to further fractionation to separate a distillate product from "reflux condensate, directing said reflux condensate to a heating coil wherein the `oil is heated to valcracking temperature, passing the re- Y sultantheated products to a reaction zone, directing the products from the catalytic cracking to said rreaction Zone, directing said mixture of unvaporized residue and lheavy reflux condensate to said reaction-.zone subjecting the resultant mixture in the reaction zone to cracking conditions'of temperature and pressure to produce further cracking and effecting a separation of residualconstituents from vapors, passing resultant separated vapors to the aforesaid fractionating Zone, subjecting said residualconstituents to coking, and passing evolved vapors from the coking operation to said fractionating zone.

2,. In the conversionof hydrocarbon oils the process that comprises vdistilling crude petroleum to separate a residue from a` lighter fraction, subjecting saidlighter fractionto catalytic cracking, introducing said residue into a fractionating Zone wherein fractionation takes place to separatea resultant mixture of unvaporized residue and heavy reflux condensate from uncondensed vapors, subjecting the uncondensed vapors to further fractionation to separate a distillate productv from reflux condensate, directing said reflux condensate toa heating coil wherein the oil is heated to a cracking temperature, passing the resultant' heated products yto a reaction zone, directing the products from the catalytic cracking to `said reaction zone, directingsaid mixture of unvaporized residue and heavy reflux condensate to said reaction zone, subjecting the resultant mixture inthe reaction zone to cracking conditions of temperature and pressure to produce furtherfcracking'and effecting a separation `of residual constituents from vapors, passing' resultant separated vapors to the aforesaid fractionating zone, subiecting said residual constitu-` ents to coking, subjecting the evolved vapors from the coking operation to a primary dephlegmation to separate a tarrv distillate, withdrawing said tarry distillate as a fuel oil product of the process and passing the dephlegmated vapors to said fractionating zone. u

3. In the conversion of hydrocarbon oils the process that comprises distilling crude petrolum to separate a residue from a lighter fraction, subjecting said lighter fraction to catalytic cracking, introducing said residue into a fractionating zone wherein fractionation takes place to separate a resultant mixture of unvaporized residue and heavy reflux condensate from uncondensed vapors, subjecting the uncondensed vapors to further fractionation to separate a distillate product from reflux condensate, directingk said reflux condensate to a heating coil wherein the oil is heated to a cracking temperature, combining the resultant heated products with the products from the catalytic cracking operation and with said mixture of unvaporized residue and heavy refiux condensate for cracking in a reaction chamber wherein separation of vapors from liquid residue takes place, maintaining cracking conditions of temperature and pressure in said reaction chamber, passing resultant separated vapors to they aforesaid lfractionating zone, 'withdrawing liquidV residuev together* with;r a portion.foff'the. vapors from the reaction chaniberand delivering the Amixture toacoking zone wherein coking takes piace,v the; proportion e of. vapors so withdrawn being sufficient to effect -autogenousfcoking of the mixture and passing evolved vapors;fr-orrithey coking operation to, said. fractionating. zone.

4, 'In the conversion ofl hydrocarbon'foils`- the process vthat comprises ,distil'lng `crude petroleum to separate a residue from a lighterfractiorfgsubje'cting said lighter fraction to catalytic cracking in a catalytic cracking zone, introducing said residue into a fractionating zone whereinfrac; tionation takes place to separate afresultant'mixture of unvaporizedresidue and heavy-refluxfcon'- ydensate from uncondensed vapors, passing uncondensed vapors to a'secondfractionating Zone wherein'the vapors are fractionated'toseparate a distillatev product. from refiuxrccndensate, directingv one portion of the reflux 'condensatefrom. the second fractionating zone tol aheating coil wherein the oil is heatedto a cracking temperature, passing the-resultant heated products to a V reaction zone, directing the products from the catalytic cracking to said reaction zone, directing saidvv mixture of Vunvaporized residue and heavy reux ,condensater to .said reaction Zone, subject-v ing the resultant mixture in the, reactionzone to.' -cracle'ng conditions oftemperature and pressure to produce further cracking and effecting a separation of residual constituentsfrom vapors, passing resultant separated vapors. tothe rst-mentioned fractionating zone, subjecting said .residual constituents to coking, passingevolved vapors to said fractionating fromfthe coking operation zone anddirecting another condensate from the second the aforesaid catalytic cracking zone. y

5.` In the conversion of hydrocarbon oils the portion of the. V-reiiux method of treating a residual stockcand a con` densate stock that comprises subjecting the condensate stock to catalytic cracking, introducing the residual stock into a fractionating zone where, in fractionation takes place to separate a Y 'resultant mixture of unvaporized residue and heavyl reflux condensate from uncondensed vapors, subfractionating'zone to.

jecting the uncondensed vapors to further, frafc-`v K tionation to separate a distillatev product ffrom reux. condensate,v directing said reiuxy condensate to a heatingfcoil wherein the', oilis heated to a. crackingr temperature, passing the:- resultant heated products to: a reaction zone, directing'the s products from the. catalytic cracking torsaidk reactionn zona directingy said mixturer of unvaporizedfresidueandv heavy reflux condensate to said reaction zone, subjecting the'resultantmixture ini theV reaction zone to cracking; conditions of. temperature; and.v pressure to produce further cracking and efecting-ahseparation of residual constituents from vapors," passing resultantk separated vapors` to' the laforesaid* fractionating Zone,- subjecting said; residual constituents to coking and. passing evolvedvap-ors'from' the cc-king operation to said fractionating zone.- j

`6. In; the conversionv of hydrocarbon oils the method oftreatng a residual stock and a condensate stock that comprises subjecting the condensate stock to catalytic cracking, introducing the residual stock into a. fractionating4 zone wherein fractionation takes place to separate a resultant mixture of unvaporized residue and heavy reux condensate from uncondensed va- Y pors, subjecting the uncondensed vapors to. further fractionation toseparate a distillate product from reflux condensate, directingrsaid reflux condensate to a heating coil. wherein'the oil is heated to a. cracking temperature, passing the resultant heated. products to areaction zone, directing said mixture of unvaporizedresidue and heavy refiux condensate to said reaction zone, subjecting the resultant mixture in the reaction zone to cracking conditions. of temperature and pressure to producefrther cracking and effecting a separation 

